Localization and delocalization of ultracold bosonic atoms in finite optical lattices

Abstract

We study bosonic atoms in small optical lattices by exact diagonalization and observe a striking similarity to the superfluid to Mott insulator transition in macroscopic systems. The momentum distribution, the formation of an energy gap, and the pair correlation function show only a weak size dependence. For noncommensurate filling we reveal in deep lattices a mixture of localized and delocalized particles, which is sensitive to lattice imperfections. Breaking the lattice symmetry causes a Bose-glass-like behavior. We discuss the nature of excited states and orbital effects by using an exact diagonalization technique that includes higher bands.

arXiv comment8 pages, 10 figures. Published version

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• Correlations of strongly interacting ultracold dipolar bosons in optical lattices
• Controlled generation of coherent matter-currents using a periodic driving field
• Correlation versus commensurability effects for finite bosonic systems in one-dimensional lattices
• Interaction Driven Interband Tunneling of Bosons in the Triple Well
• Probing condensate order in deep optical lattices
• Finite-size effects in Anderson localization of one-dimensional Bose-Einstein condensates
• Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems
• Excitation spectrum of Mott shells in optical lattices
• Ultracold bosons in one-dimensional harmonic and multi-well traps: a Quantum Monte Carlo vs a correlated pair approach
• Global and local condensate and superfluid fraction of a few hard core bosons in a cubic optical lattice plus external harmonic confinement
• Tunneling of a few strongly repulsive hard-sphere bosons in an optical lattice with tight external harmonic confinement: A quantum Monte Carlo investigation in continuous space
• Localization-Delocalization Transition and Current Fractalization